Re: [PATCH 04/27] ext2: Add ext2_sb_info mutex

[Jan Blunck]

 On Mon, Nov 02, Andi Kleen wrote:

> > @@ -762,6 +767,12 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent)
> >  	sbi->s_sb_block = sb_block;
> >  
> >  	/*
> > +	 * mutex for protection of modifications of the superblock while being
> > +	 * write out by ext2_write_super() or ext2_sync_fs().
> > +	 */
> > +	mutex_init(&sbi->s_mutex);
> 
> I didn't go over all the code paths in detail, but if you replace
> the BKL with a mutex that is hold over a longer write-out sleep
> period you potentially limit IO parallelism a lot.

Right. I converted it to be a spinlock and unlock before calling
ext2_sync_super().

What do you think?

Thanks,
Jan